The K05 award will provide Dr. Thomas L Vaughan with protected time (30% FTE) to pursue key research questions related to the etiology and prevention of esophageal adenocarcinoma, a cancer that has increased over six-fold in incidence over three decades. It will also provide for protected time (20% FTE) to expand his already extensive mentoring activities of students and other junior investigators at the University of Washington (UW) and the Fred Hutchinson Cancer Research Center (FHCRC). Dr. Vaughan was one of the founders of the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON), an international consortium of over 30 investigators representing 16 studies, supported in part by NCI and NIDDK, and was elected as the first Chair of the Steering Committee. The research aspects of this award will be conducted in the context of the BEACON, and consist of: i) continued analyses of data and tissue collected as part of a community-based case-control studies of incident Barrett's for which Dr. Vaughan was PI, ii) pooled analyses of data from multiple population-based studies carried out by BEACON investigators, and iii) development of new collaborative research projects within BEACON that take advantage of the diverse populations represented, and existing banks of well-characterized tissues. Dr. Vaughan has a well-established track record of mentoring graduate students and postdoctoral fellows, as well as junior faculty in Epidemiology and related disciplines. He was Co-director of the Environmental Epidemiology Training Grant from 1990-2006;in 2005 he assumed responsibility as Director of the NCI-funded Cancer Epidemiology and Biostatistics Training Grant (T32CA09168). He is a frequent guest lecturer in established epidemiology courses, and has served on 23 masters thesis committees and 20 doctoral dissertation committees. Expanded mentoring activities on the K05 will include: i) those associated with his responsibilities on the training grant, ii) his ongoing mentoring of other trainees from Epidemiology and related departments, and junior faculty across public health disciplines at the UW and FHCRC, and iii) two new pre- or post-doctoral students working directly on K05-associated research activities.